U.S. patent application number 14/653172 was filed with the patent office on 2016-07-07 for plasticizer free caulks and sealants comprising waterborne acrylic polymeric composites and methods for making the same.
The applicant listed for this patent is ROHM AND HAAS COMPANY. Invention is credited to Karl Allen Bromm, Victoria A. Demarest, Catheryn L. Jackson, Willie Lau, Audrey B. Liss.
Application Number | 20160194505 14/653172 |
Document ID | / |
Family ID | 49885456 |
Filed Date | 2016-07-07 |
United States Patent
Application |
20160194505 |
Kind Code |
A1 |
Lau; Willie ; et
al. |
July 7, 2016 |
PLASTICIZER FREE CAULKS AND SEALANTS COMPRISING WATERBORNE ACRYLIC
POLYMERIC COMPOSITES AND METHODS FOR MAKING THE SAME
Abstract
The present invention provides aqueous caulk or sealant
compositions that are substantially free of any plasticizer
comprising an aqueous emulsion copolymer having a broad measured
glass transition temperature by differential scanning calorimetry
(DSC), soft phases and hard phases, and two separate Tan Delta
transition temperatures as measured by dimensional mechanical
analysis (DMA), (ii) one or more filler in a filler to binder ratio
of up to 4:1, and (iii) from 0.2 to 5 wt. % as solids, based on the
total weight of the composition, of one or more thickener or
rheology modifier. In addition, the invention provides methods of
making the composition comprising polymerizing by gradually adding
from a flask into a polymerization vessel a soft monomer
composition, and, after feeding at least 20 wt. % of such
composition in the vessel, gradually adding into the flask a hard
comonomer composition, feeding all flask contents into the vessel
and polymerizing.
Inventors: |
Lau; Willie; (Lower Gwynedd,
PA) ; Bromm; Karl Allen; (Forest Grove, PA) ;
Demarest; Victoria A.; (Flourtown, PA) ; Jackson;
Catheryn L.; (Lansdale, PA) ; Liss; Audrey B.;
(Newtown, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROHM AND HAAS COMPANY |
Philadelphia |
PA |
US |
|
|
Family ID: |
49885456 |
Appl. No.: |
14/653172 |
Filed: |
December 12, 2013 |
PCT Filed: |
December 12, 2013 |
PCT NO: |
PCT/US13/74557 |
371 Date: |
June 17, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61739090 |
Dec 19, 2012 |
|
|
|
Current U.S.
Class: |
524/507 ;
524/522; 524/733; 524/833 |
Current CPC
Class: |
C08F 220/1804 20200201;
C08F 220/18 20130101; C08F 220/1804 20200201; C08F 220/1804
20200201; C08F 220/1808 20200201; C09K 3/1006 20130101; C09D 133/12
20130101; C08F 220/18 20130101; C09K 2200/0625 20130101; C08F
220/06 20130101; C08F 220/1808 20200201; C08F 220/06 20130101; C08F
220/06 20130101; C08F 220/06 20130101; C08F 220/06 20130101; C08F
220/14 20130101; C08F 220/06 20130101; C08F 220/14 20130101; C08F
220/14 20130101; C08F 220/14 20130101; C08F 220/18 20130101; C08F
2/001 20130101; C08F 220/1808 20200201; C08F 220/1808 20200201;
C09D 5/34 20130101; C08F 220/14 20130101; C08F 220/14 20130101;
C08F 220/1808 20200201 |
International
Class: |
C09D 5/34 20060101
C09D005/34; C09D 133/12 20060101 C09D133/12 |
Claims
1. An aqueous caulk or sealant composition that is substantially
free of any plasticizer comprising (i) an aqueous emulsion
copolymer having a broad measured glass transition temperature
(broad measured Tg) by differential scanning calorimetry (DSC), a
soft phase and hard phase domains, and two separate Tan Delta
transition temperatures as measured by dynamic mechanical analysis
(DMA), which is the copolymer of a soft monomer composition which
is a soft monomer or soft monomer mixture, which soft monomer
composition would when polymerized provide a polymer having a
calculated Tg of -20.degree. C. or less, and of a hard comonomer
composition which is a hard comonomer or hard comonomer mixture,
which hard comonomer composition would when polymerized provide a
polymer having a calculated Tg of from 20.degree. C. to 140.degree.
C., (ii) one or more filler in a filler to binder ratio of from 0:1
to 4:1 (iii) from 0.2 to 5 wt. % as solids, based on the total
weight of the composition, of one or more thickener or rheology
modifier and, (iv) less than 50% of water to adjust viscosity,
wherein the caulk and sealant compositions have a solids content
ranging from 50 to 80 wt. % and the compositions have a Brookfield
viscosity (room temperature, 5 rpm, using a T-Bar type T-F spindle
for compositions with viscosities above 1,000,000 cPs, and a T-Bar
type T-E spindle for compositions with viscosities of from 3,000
and 1,000,000 cPs) of from 3,000 to 1,000,000 cPs.
2. The composition as claimed in claim 1, wherein the soft monomer
composition would when polymerized provide a polymer having a
calculated Tg of -30.degree. C. or less.
3. The composition as claimed in claim 1, wherein at least one of
the soft monomer composition and hard comonomer composition is
acrylic.
4. The composition as claimed in claim 1, wherein the emulsion
copolymer comprises, in copolymerized form, an ethylenically
unsaturated acidic monomer, in the amount of from 0.1 to 5 wt. %
based on the total weight of monomers used to make the emulsion
copolymer.
5. The composition as claimed in claim 1, the thickener or rheology
modifier is chosen from cellulosics, kaolin, polyacrylic acid
salts, hydrophobic alkali soluble emulsion polymers, polyurethane
thickeners, and mixtures thereof.
6. The composition as claimed in claim 1, comprising 0.5 wt. % or
less of plasticizer, based on the total weight of the
composition.
7. The composition as claimed in claim 1, further comprising one or
more organosilane adhesion promoter.
8. A method of making an aqueous caulk and sealant composition that
is substantially free of plasticizer and has a Brookfield viscosity
(room temperature, 5 rpm, using a T-Bar type T-F spindle for
compositions with viscosities above 1,000,000 cPs, and a T-Bar type
T-E spindle for compositions with viscosities of from 3,000 and
1,000,000 cPs) of from 3,000 to 1,000,000 cPs comprising: a)
gradually feeding from a soft monomer vessel a soft monomer
composition which is a soft monomer or soft monomer mixture, which
composition would when polymerized provide a polymer having a
calculated Tg of -20.degree. C. or less, and aqueous emulsion
polymerizing the soft monomer composition in the polymerization
vessel, wherein the polymerizing also comprises co-feeding a buffer
into the polymerization vessel during the feed of the soft monomer
composition into the polymerization vessel; b) after feeding no
less than 20 wt. % of the total soft monomer composition into the
polymerization vessel, gradually feeding a hard comonomer
composition which is a hard comonomer or hard comonomer mixture
into the soft monomer vessel, which hard comonomer composition
would when polymerized provide a polymer having a calculated Tg of
from 20.degree. C. to 140.degree. C., while continuing to gradually
feed all monomers remaining in the soft monomer vessel into the
polymerization vessel and polymerizing the soft monomer composition
and the hard comonomer composition to form an aqueous emulsion
copolymer having a soft phase and hard phase domains and two
separate Tan Delta transition temperatures as measured by
dimensional mechanical analysis (DMA); and, c) combining with the
aqueous emulsion copolymer from 0.2 to 5 wt. %, based on the total
weight of the composition, of one or more aqueous thickener or
rheology modifier to form the composition.
9. The method as claimed in claim 8, comprising b) gradually
feeding the hard comonomer into the soft monomer vessel after from
20 to 85 wt. % of the soft monomer composition is fed into the
polymerization vessel.
10. A method of using the aqueous caulk and sealant composition of
claim 1, comprise applying the composition to a substrate chosen
from glass, mortar, aluminum, wood, vinyl, fiber cement, brick,
concrete block, painted surfaces, combinations thereof, joints
therein, seams therein, gaps therein, joints between substrate
pieces and gaps between substrate pieces.
Description
[0001] The present invention relates to filled aqueous caulks and
sealants that are substantially free of any plasticizer and deliver
excellent performance over a wide temperature range comprising
copolymers having separate soft and hard phases, and to uses
thereof as caulks and sealants and the methods of making them. More
specifically, it relates to aqueous caulks and sealants which
comprise acrylic powerfeed aqueous emulsion copolymers having a
broad measured glass transition temperature (measured Tg) which are
the copolymerization product of a monomer composition which when
polymerized would provide a polymer having a calculated Tg of below
-20.degree. C. and second monomer composition which when
polymerized would provide a polymer having a calculated Tg of from
20.degree. C. to 140.degree. C. as well as to methods of making the
same.
[0002] Acrylic and other conventional emulsion polymers are known
to provide weatherable caulks and sealants. However, such polymers
that are soft for ease of application and low temperature
flexibility to accommodate joint movement present an inability to
provide adequate block resistance and durability in use, especially
at above room temperature. Meanwhile, such polymers that are hard
for durability and low tack reasons are generally difficult to use
without including plasticizers. Plasticizers are undesirable
because they are expensive and many of them may be unsafe to use.
In addition, plasticizers remain permanently in the polymer phase
contributing to undesirable tackiness and increased dirt pick
up.
[0003] For aqueous caulk and sealant applications, several emulsion
polymer binders that have a broad range of hardness as determined
by glass transition temperature (Tg), are commercially available.
Each of such conventional emulsion polymers has a single Tg and
provides inferior performance properties as one gets further away
from the Tg temperature of the emulsion polymer. Hence, properties
that would characterize high Tg polymers, such as hardness, low
tack and toughness are compromised in soft polymers. And properties
that would characterize low Tg polymers, such as softness and low
temperature film formation and flexibility are compromised in high
Tg polymers.
[0004] Japan unexamined patent application no. 2000-319301A, to
Showa Highpolymer Ltd., discloses power feed emulsion copolymers
for use in coatings, wherein the emulsion copolymers comprise the
polymerization product of an ethylenically unsaturated compound
that gives a polymer Tg of -30.degree. C. or lower and an
ethylenically unsaturated compound that gives a polymer Tg of
30.degree. C. or higher. The Japan published application mentions
nothing of caulks and sealants and provides no way to make a caulk
or sealant.
[0005] The present inventors have endeavored to solve the problem
of providing a plasticizer free caulk or sealant comprising an
acrylic emulsion copolymer binder which provides flexibility, low
tack and tensile properties at a wide range of temperatures and use
conditions.
STATEMENT OF THE INVENTION
[0006] 1. In accordance with the present invention, aqueous caulk
and sealant compositions that are substantially free of any
plasticizer comprise (i) an aqueous emulsion copolymer having a
broad measured glass transition temperature (broad measured Tg) by
differential scanning calorimetry (DSC), a soft phase and hard
phase domains and two separate Tan Delta transition temperatures as
measured by dimensional mechanical analysis (DMA), which is the
copolymer of a soft monomer composition which is a soft monomer or
soft monomer mixture, which soft monomer composition would when
polymerized provide a polymer having a calculated Tg of -20.degree.
C. or less, or, preferably, -30.degree. C. or less, or, more
preferably, -40.degree. C. or less, and of a hard comonomer
composition which is a hard comonomer or hard comonomer mixture,
which hard comonomer composition would when polymerized provide a
polymer having a calculated Tg of from 20.degree. C. to 140.degree.
C., or, preferably, 25.degree. C. or higher, or, preferably,
125.degree. C. or less, (ii) one or more filler in a filler to
binder ratio of from 0:1 to 4:1, for example, 0.25:1 or higher, or
3.5:1 or less, (iii) from 0.2 to 5 wt. % as solids, based on the
total weight of the composition, preferably, 0.5 wt. % or more, or,
preferably, 3 wt. % or less, of one or more thickener or rheology
modifier and, (iv) water to adjust viscosity, wherein the caulk and
sealant compositions have a solids content ranging from 50 to 80
wt. % and the compositions have a Brookfield viscosity (room
temperature, 5 rpm, using the indicated spindle) of from 3,000 to
1,000,000 cPs, preferably, 10,000 cPs or more or, preferably,
500,000 cPs or less. The caulk and sealant compositions are
substantially free of plasticizer, and, preferably, comprise 0.5
wt. % or less of plasticizer, based on the total weight of the
composition.
[0007] 2. Preferably, the emulsion copolymer in the compositions of
item 1 is the copolymer of from 20 to 90 wt. %, preferably, from 50
to 80 wt. %, or, more preferably, from 65 to 80 wt. % of the soft
monomer composition, based on the total weight of monomers used to
make the emulsion copolymer.
[0008] 3. Preferably, at least one of the soft monomer composition
and hard comonomer composition is acrylic, or, more preferably, the
emulsion copolymer comprises 80 wt. % or more, based on the total
weight of monomers used to make the emulsion copolymer, of the
product of copolymerizing acrylic monomer(s).
[0009] 4. Preferably, at least one of the soft monomer composition
or the hard comonomer composition in items 1 or 2 comprises, in
copolymerized form, an ethylenically unsaturated acidic monomer, in
the amount of from 0.1 to 5 wt. % based on the total weight of
monomers used to make the emulsion copolymer, or, more preferably,
a carboxylic acid, salt or anhydride group containing monomer, or,
most preferably, acrylic or methacrylic acid.
[0010] 5. Preferably, in the aqueous compositions of any of items 1
to 4, the thickener or rheology modifier is chosen from
cellulosics, kaolin, polyacrylic acid salts, hydrophobic alkali
swellable emulsion polymers, polyurethane thickeners, and mixtures
thereof.
[0011] 6. Preferably, the aqueous compositions of any of items 1 to
5 further comprise one or more organosilane, such as an
epoxysilane.
[0012] 7. In accordance with another aspect of the present
invention, methods of making aqueous caulk and sealant compositions
that are substantially free of any plasticizer and have a
Brookfield viscosity (room temperature, 5 rpm) of from 3,000 to
1,000,000 cPs, preferably, 10,000 cPs or more or, preferably,
300,000 cPs or less and shear (s.sup.-1) comprise a) gradually
feeding from a soft monomer vessel into a polymerization vessel a
soft monomer composition which is a soft monomer or soft monomer
mixture, which composition would when polymerized provide a polymer
having a calculated Tg of -30.degree. C. or less, or, preferably,
-40.degree. C. or less, or, more preferably, -50.degree. C. or
less, and aqueous emulsion polymerizing the soft monomer
composition in the polymerization vessel and, b) after feeding no
less than 20 wt. % of the total soft monomer composition into the
polymerization vessel, gradually feeding a hard comonomer
composition which is a hard comonomer or hard comonomer mixture
into the soft monomer vessel, which hard comonomer composition
would when polymerized provide a polymer having a calculated Tg of
from 20.degree. C. to 140.degree. C., or, preferably, 25.degree. C.
or higher, or, preferably, 125.degree. C. or less, while continuing
to gradually feed all monomers remaining in the soft monomer vessel
into the polymerization vessel and polymerizing the soft and hard
monomer compositions to form an aqueous emulsion copolymer having a
soft phase and hard phase domains and two separate Tan Delta
transition temperatures as measured by dynamic mechanical analysis
(DMA), and c) combining with the aqueous emulsion copolymer from
0.2 to 5 wt. %, based on the total weight of the composition,
preferably, from 0.4 to 3 wt. %, of one or more aqueous thickener
or rheology modifier to form the composition.
[0013] 8. In item 7, above, gradually feeding the hard comonomer
composition into the soft monomer vessel after from 20 to 85 wt. %,
or, preferably, 50 to 75 wt. % of the total soft monomer
composition has been fed into the polymerization vessel.
[0014] 9. In accordance with another aspect of the present
invention, methods of using the aqueous caulk and sealant
composition of any of items 1 to 6, above, comprise applying the
composition to a substrate chosen from glass, mortar, aluminum,
wood, vinyl, fiber cement, brick, concrete block, painted surfaces,
combinations thereof, joints therein, seams therein, gaps therein,
joints between substrate pieces and gaps between substrate
pieces.
[0015] All ranges are inclusive and combinable. For example, a
stated range of from 0.2 to 5 wt. %, based on the total weight of
the composition, preferably, 0.4 wt. % or more, or, preferably, 3
wt. % or less of one or more thickener or rheology modifier refers
to from 0.3 to 5 wt. %, from 0.3 to 3 wt. %, from 0.4 to 3 wt. %,
and from 0.4 to 5 wt. %.
[0016] Unless otherwise indicated, any term containing parentheses
refers, alternatively, to the whole term as if no parentheses were
present and the term without them (i.e. excluding the content of
the parentheses), and combinations of each alternative. Thus, the
term "(meth)acrylic" refers to any of acrylic, methacrylic, and
mixtures thereof.
[0017] Unless otherwise specified, all temperature units refer to
room temperature (-20-24.degree. C.) and all pressure units refer
to standard pressure.
[0018] As used herein, the phrase "acrylic" refers to acrylic or
methacrylic acid, salt, anhydride, ester, or amide monomers or the
polymerization products thereof. When referring to emulsion
copolymers, the term "acrylic" refers to polymers which comprise at
least 50 wt. %, in copolymerized form, based on the weight of all
monomers used to make the polymer, of acrylic monomers.
[0019] As used herein, the phrase "aqueous" includes water and
mixtures comprising 50 wt. % or more of water in a mixture of water
with water-miscible solvents that are volatile in use
conditions.
[0020] As used herein, the term "Brookfield viscosity" refers to
the room temperature composition viscosity as measured on a
Brookfield RV DV-I viscometer with a
[0021] Brookfield HELIPATH.TM. stand using a T-Bar type T-F spindle
for compositions with viscosities above 1,000,000 cPs, a T-Bar type
T-E spindle for compositions with viscosities of from 3,000 and
1,000,000 cPs. The speed of rotation of the spindle in all cases is
1 rpm and the spindle is run for 10 seconds before the measurement
is made. The Brookfield Helipath.TM. stand allows the spindle to
move down into the composition during rotation to ensure proper
measurement of highly viscous materials.
[0022] As used herein, the term "calculated glass transition
temperature" or "calculated Tg" refers to the calculated glass
transition temperature of homopolymers or (co)polymers, as
determined using the Fox equation (T. G. Fox, Bull. Am. Physics
Soc., Volume 1, Issue No. 3, page 123 (1956)). For example, to
calculate a Tg of a copolymer of monomers M1 and M2,
1/Tg=w(M1)/Tg(M1) +w(M2)/Tg(M2), wherein w(M1) is the weight
fraction of monomer M1 in the copolymer, w(M2) is the weight
fraction of monomer M2 in the copolymer, Tg(M1) is a published
glass transition temperature ("Fox Tg") of a high molecular weight
homopolymer (>50 k weight average MW) of M1, Tg(M2) is a
published glass transition temperature of a high molecular weight
homopolymer of M2, and all temperatures are in .degree. K. Suitable
published glass transition temperatures are available at, for
example,
http://www.sigmaaldrich.com/img/assets/3900/Thermal_Transitions_of_Homopo-
lymers. pdf. For example, the calculated Tg or glass transition
temperature of a soft monomer alone is the glass transition
temperature of a homopolymer of that soft monomer having a weight
average MW of 50,000 or more; and the calculated Tg or glass
transition temperature of a soft monomer mixture is the glass
transition temperature of a copolymer of that soft monomer mixture
having a weight average MW of 50,000 or more as given by the Fox
equation.
[0023] As used herein the phrase "measured glass transition
temperature" or "measured T.sub.g" refers to the glass transition
temperature of a material as determined by Differential Scanning
calorimetry (DSC) scanning from -90.degree. C. to 150.degree. C. at
a rate of 20.degree. C/min on a DSCQ2000 manufactured by TA
Instrument, New Castle, Del. The T.sub.g is the inflection point of
the curve of heat flow vs. temperature or the maximum value on the
plot of its derivative.
[0024] As used herein, the term "broad measured glass transition
temperature (broad measured Tg)" refers to a DSC glass transition
wherein either the onset or final temperature of the recorded
temperature curve are poorly defined such that no meaningful single
measured Tg can be taken, and instead only a range of measured Tgs
can be recorded. An example of a polymer having a broad measured Tg
is a powerfeed emulsion copolymer.
[0025] As used herein, the term "Dynamic mechanical analysis" or
"DMA" refers to the method used to measure G' (loss modulus) and
G'' (storage modulus) over a predetermined range of temperature,
typically set at -200.degree. C. to 150.degree. C., where G' is the
energy dissipated as heat, representing the viscous portion of the
polymer, and G'' is the stored energy, representing the elastic
portion of the polymer. In the present invention, DMA is measured
with a dry polymer film tested in shear mode on the Rheometrics
Mechanical Spectrometer (RMS-800) instrument using 8 mm diameter
disposable parallel plate fixtures. Prior to measurement, the
thickness of dry sample is measured to the nearest 0.001 mm and the
data is input into the instrument to calculate the shear moduli. A
temperature sweep was run from 150.degree. C. to -50.degree. C. at
a cooling rate of 2.degree. C/min using the Dynamic Temperature
Ramp Mode. The applied frequency was 6.28 rad/s (1 Hz) and both
AutoTension and AutoStrain options were employed during the test.
The initial strain was 0.25%. The dynamic storage and loss moduli
(G' and G'' respectively) as well as tan 6 were recorded as a
function of temperature. The G' and G'' as measured over the
temperature range represent the polymer dynamic transition from a
glassy state to the rubbery state and can be related to the Tg of
the polymer. The Tan Delta, defined as the ratio of G'/G'',
provides one or more Tan Delta peak or transition temperatures over
the predetermined range of temperature and is an alternative way to
measure polymer Tg. In general, for a given polymer, a Tan Delta
peak temperature will be -10.degree. C. higher than the
corresponding Tg for the same polymer as measured by DSC.
[0026] As used herein, the phrase "filler to binder ratio" refers
to the total weight of fillers and pigments (solids) to the total
weight of aqueous binder solids (emulsion copolymer solids).
[0027] As used herein, the phrase "nonionic monomer" refers to any
monomer such that the copolymerized monomer residue of which does
not bear an ionic charge under conditions of use and over the pH
range of pH 2-12.
[0028] As used herein, unless otherwise indicated, the phrase
"polymer" includes homopolymers, and the phrase "copolymer" refers
to any polymers made from two or more different monomers, including
terpolymers, block copolymers, segmented copolymers, multi-staged
copolymers, graft copolymers, and any mixture or combination
thereof.
[0029] As used herein the phrase "substantially free of any
plasticizer" refers to any composition which comprises 0.5 wt. % or
less, based on the total weight of the composition.
[0030] As used herein, the phrase "weight average particle size"
refers to the weight average particle size of a material as
determined using capillary hydrodynamic fractionation (CHDF) with a
Matec CH DF 2000 chromatography system (Matec Applied Sciences,
Northborough, Mass.).
[0031] The present invention provides aqueous caulk and sealant
compositions wherein the emulsion polymer binders have a broad
measured Tg (by DSC) and both a soft phase and hard phase domains
as indicated by the presence of two Tan Delta transitions for the
emulsion polymer when measured by DMA. The aqueous compositions
have the ability to deliver consistent performance at cold and warm
temperatures. Made by a powerfeed emulsion polymerization process,
the aqueous emulsion copolymer binders provide a compositional
profile in use with a soft continuous phase and reinforcing hard
microdomains that behaves like a composite. The emulsion copolymers
retain this behavior without the use of plasticizers which can
adversely impact the separation of the phases; thus, surprisingly,
the present invention provides caulk or sealant compositions which
give improved performance at a wide range of use temperatures
precisely because they are substantially or completely plasticizer
free. For the emulsion copolymer binders of the present invention,
there are two Tan Delta transition temperatures or peaks measured
by DMA and signifying the presence of two polymer phases having
differing hardnesses as compared to a single peak for the random
copolymers. Accordingly, the present invention provides caulk and
sealant compositions having improved performance properties
throughout a range of temperatures while maintaining the easy
cleaning attributes of an acrylic composition.
[0032] The emulsion copolymer binders of the present invention have
a phase formed from the polymerization of a soft monomer
composition, which composition would when homopolymerized provide a
polymer having a calculated Tg of -20.degree. C. or less, or,
preferably, -30.degree. C. or less, or, more preferably,
-40.degree. C. or less. Suitable soft monomers may include, for
example, butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), ethyl
acrylate (EA); alkyl vinyl ethers; and C.sub.8 to C.sub.30 alkyl
(meth)acrylates, such as fatty (meth)acrylates like dodecyl
methacrylate and octadecyl methacrylate. The soft monomer
compositions may include harder monomers so long as the copolymer
made from them has the calculated glass transition temperature of
-20.degree. C. or less as indicated in the statement of the
invention, above.
[0033] The emulsion copolymer binders of the present invention have
dispersed phases formed from the polymerization of a hard comonomer
composition, which composition would, when homopolymerized, provide
a polymer having a calculated Tg of from 20.degree. C. to
140.degree. C., or, preferably, 25.degree. C. or higher, or,
preferably, 125.degree. C. or less. Suitable hard comonomers may
include, for example, methyl methacrylate (MMA), isobutyl
methacrylate, alicylic and aromatic (meth)acrylates, such as
isobornyl methacrylate, cyclohexyl methacrylate; and arylene
monomers, such as styrene and methyl styrene. Acidic monomers are
also hard comonomers. The hard comonomer compositions may include
softer monomers so long as the copolymer made from them has the
calculated Tg of from 20 to 140.degree. C.
[0034] The emulsion copolymers of the present invention may
preferably include in their copolymerized form acidic monomers,
such as mono-and di-carboxylic acid monomers. Suitable mono-and
di-carboxylic acid monomers may include, for example, methacrylic
acid (MAA), acrylic acid (AA), itaconic acid (IA), maleic acid
(MA), and fumaric acid (FA), salts thereof and anhydrides thereof.
Suitable sulfur acid containing monomers may include, for example,
styrene sulfonate and acrylamidopropane sulfonate and their salts.
Suitable phosphorus containing acids may include, for example, any
phosphorus containing acids possessing at least one PON group in
which the hydrogen atom is ionizable, and their salts, such as
phosphoalkyl (meth)acrylates like 2-phosphoethyl methacrylate
(PEM), di-, tri-, or poly-phosphate ester group containing
(meth)acrylates; alkylvinyl phosphonates and their salts; monomers
containing groups formed from phosphinic acid, phosphonic acid,
phosphoric acid, pyrophosphinic acid, pyrophosphoric acid, partial
esters thereof, and salts thereof. Preferably, the acidic monomer
is chosen from methacrylic acid, acrylic acid, and/or PEM.
[0035] Suitable binder copolymers are copolymerized from total
amounts of one or more acidic monomer ranging up to 10.0 wt. %,
based on total copolymerized monomer weight, or, preferably, 0.1
wt. % or higher, or 0.3 wt. % or higher, or 0.5 wt. % or higher,
preferably, 5.0 wt. % or less, or, more preferably, 4.0 wt. % or
less.
[0036] Preferably, to achieve transparency, the emulsion copolymers
of the present invention have the ability to dry clear because of
their small hard phases or microdomains, for example with an
average particle size of 100 nm or less, preferably 50 nm or less
(via light scattering), distributed in the continuous phase.
Accordingly, the emulsion copolymers of the present invention can
be formulated into clear caulks and sealants.
[0037] Preferably, the emulsion copolymers of the present invention
are formed by a powerfeed process. In powerfeed polymerization, the
soft monomer composition is gradually fed into a polymerization
vessel over a total monomer feed time and, after a time period that
begins with the start of the soft monomer composition feed and ends
when the start of the hard monomer composition feed the hard
comonomer composition is fed into the soft monomer composition
while the soft monomer composition is fed into the polymerization
vessel. In the methods of the present invention, the time period or
delay from the beginning of the total monomer feed time (the time
at which the soft monomer composition feed into the polymerization
vessel is started) to the time at which the hard comonomer
composition is fed into the soft monomer composition is expressed
as a percentage of the total monomer feed time. It is this time
period that enables the provision of separate hard and soft phases
in the aqueous emulsion copolymer of the present invention.
[0038] More preferably, the total monomer feed time for the soft
monomer composition and for the hard monomer composition ends
simultaneously.
[0039] More preferably, the methods of making aqueous emulsion
copolymers comprises starting the feed of the hard comonomer
composition into the soft monomer composition (and from there into
the polymerization vessel) after feeding from 20 to 85 wt. %, or,
preferably, 50 to 75 wt. %, of the total soft monomer composition
into the polymerization vessel.
[0040] Preferably, the feed rate of soft monomer composition is
held constant.
[0041] Preferably, the feed rate of the hard comonomer composition
is adjusted to end at same time as the soft monomer composition
feed.
[0042] The aqueous binder copolymers of the present invention have
solids contents of 30 wt. % or higher and up to 70 wt. %, based on
the total weight of the aqueous copolymer, or, preferably, 45 wt. %
or higher, or up to 70 wt. %.
[0043] The emulsion copolymers of the present invention may be made
via semicontinuous conventional emulsion polymerization methods. In
the polymerization, either thermal or redox initiation processes
may be used. The reaction temperature may be maintained at a
temperature lower than 100.degree. C. throughout the course of the
reaction, preferably from 30.degree. C. to 95.degree. C.
Conventional feeding devices such as metering devices, feed vessels
and reaction vessels may be used.
[0044] Polymerization reagents may include, for example, known
catalysts including thermal initiators, like peracids or their
salts, like persulfates, peroxides, or bis-nitriles; redox pairs,
such as peroxides and (bi)sulfites. Initiators and redox catalysts
may be used at levels of 0.01 to 3.0 wt. %, based on the total
weight of monomers used to make the emulsion copolymer.
[0045] In polymerization, conventional emulsifiers and/or
dispersants may be used, such as, for example, anionic and/or
nonionic emulsifiers such as, for example, alkali metal or ammonium
salts of alkyl, aryl, or alkylaryl sulfates, sulfonates or
phosphates; alkyl sulfonic acids; sulfosuccinate salts; fatty
acids; ethylenically unsaturated surfactant monomers; and
ethoxylated alcohols or phenols. The amount of surfactant used is
usually 0.1% to 6% by weight, based on the weight of monomer.
[0046] In polymerization, conventional chain transfer agents such
as mercaptans, like n-dodecyl mercaptan (nDDM) may be used. The
chain transfer agents may optionally be added in conventional
amounts, such as from 0.1 to 20 wt. %, preferably, less than 5 wt.
%, based on the total weight of monomers and initiators. In
addition, the chain transfer agents may be added in the powerfeed
method into the soft monomer composition, which results in a
molecular weight gradient in the polymer.
[0047] Preferably, to insure a stable aqueous emulsion copolymer
having a low viscosity, the polymerization process comprises
co-feeding a buffer such as Na.sub.2CO.sub.3 or Na.sub.2SO.sub.4 to
the polymerization vessel during polymerization to maintain the
polymerization medium at a pH of 5 or less, such as from 4-5. A
buffer co-feed can continue throughout the duration of the soft
monomer composition feed into the polymerization vessel, or during
the feeding of from 50 to 100 wt. % of the soft monomer composition
feed. More preferably, when the buffer is used, no neutralizing
agent, e.g. ammonia, is used; this avoids undue thickening of the
emulsion copolymer composition.
[0048] Preferably, during polymerization, the co-feeding of the
buffer during polymerization takes place before the gradual feeding
of the hard comonomer composition.
[0049] Following polymerization, initiators, optionally combined
with reducing agents, may be used to minimize residual monomer
content. In some cases the choice of initiator and accompanying
chemicals, their level and method of addition, and the temperature
can be chosen to affect a desired balance of the mechanical
properties in the final binder. This process may be carried out in
the same reaction or in a different vessel or kettle as was used
for the polymerization.
[0050] Suitable aqueous binder copolymers may have weight average
molecular weights ranging from 20,000 to 5,000,000 or more,
preferably, 25,000 to 1,000,000. The upper limit of molecular
weight is generally not limited and depends on the polymerization
method used. For example, higher molecular weight aqueous emulsion
copolymers will result from starting with seed polymers in the
polymerization vessel. Optionally, a crosslinking agent can be used
to increase the weight average molecular weight of the emulsion
copolymers. Suitable crosslinking agents may include, for example,
glycol di(meth)acrylates.
[0051] The aqueous compositions comprise one or more thickener or
rheology modifier, such as a cellulosic thickener, such as, for
example, hydroxyethyl cellulose ("HEC"); kaolin;
hydrophobically-modified alkali swellable emulsions ("HASE")
thickeners; polyacrylic acid salt thickeners ("ASE"); and
polyurethane thickeners, such as hydrophobically-modified,
ethoxylated urethane thickener ("HEUR").
[0052] Preferably, the one or more thickener or rheology modifier
is chosen from HEC, HASE, ASE and HEUR. Examples of preferred
thickeners include ACRYSOL.TM. TT-615 HASE thickener and
ACRYSOL.TM. RM-12W HEUR thickener, both of which are available from
the Dow Chemical Co, Midland, Mich.
[0053] In formulating the aqueous compositions, the pH of the
composition can be adjusted depending on the kind of thickener used
and acid content of the polymer. For the compositions that comprise
of high acid containing binders (3-5 wt. % ethylenically
unsaturated acidic monomers, based on total monomer weight) and/or
alkali activated thickeners with HASE or ASE, the pH of the
composition can be adjusted to 8 to 10 to achieve optimal
thickening and the pH is kept below 5 until formulation. For the
compositions that comprise of low acid containing binders (<2
wt. % ethylenically unsaturated acidic monomer) and/or non-ionic
thickeners, such as HEC and HEUR or slightly basic fillers which
thicken compositions, such as CaCO.sub.3, thickening depends on the
amount of thickener or basic filler.
[0054] The aqueous caulk or sealant compositions may be prepared
from the aqueous emulsion copolymers by techniques which are well
known in the sealants art. For example, the aqueous emulsion
copolymer binder is added directly to a kettle, followed by the
thickeners and additional ingredients and, lastly, by any filler
and pigment. Mixing may be done in a high shear mixer with a sweep
arm designed to pull the high viscosity sealant into the center of
the mixer, or in a planetary mixer, with or without a high speed
disperser blade. After all of the ingredients are added, the
sealant is allowed to mix under a vacuum of 750 mm Hg or lower to
remove entrapped air from the final product.
[0055] The aqueous caulks and sealants may have filler to binder
(solids weight) ratios of from 0:1 (no filler) to 4:1 and may
include nanoparticle extenders, such as colloidal silica, for clear
compositions or, for filled or colored compositions, a solids
weight ratio of from 0.04:1 to 4:1 of filler to binder. To improve
glass adhesion and joint movement performance in the absence of
plasticizer, caulks and sealants may have a filler to binder ratio
of 2:0:1 or less, or preferably 0.2:1 or more. However, the present
invention enables the provision of high performance clear caulks
and sealants comprising conventional ingredients without
plasticizers with desirable properties at a broad range of
temperatures above and below the Tg of the composition as a random
copolymer.
[0056] Suitable fillers may include, for example, alkaline earth
metal sulfates or carbonates, such as, for example, barites,
calcium carbonate, calcite and magnesium carbonate; silicates, such
as, for example, calcium silicates, magnesium silicates, and talc;
metal oxides and hydroxides, such as, for example, titanium
dioxide, alumina and iron oxides; diatomaceous earth; colloidal
silica; fumed silica; carbon black; white carbon black; nutshell
flour; natural and synthetic fibres (especially plaster fibres);
and scrap or recycled plastics in the form of dust, flakes or
flour; hollow or solid ceramic, glass or polymeric
microspheres.
[0057] An extender is any filler having an index of refraction of
1.4 or less. Examples of extenders include, for example, barites,
calcium carbonate, and nanosized silica. Extenders are any having
an average particle diameter below 50 nm, or, preferably, below 20
nm.
[0058] To enable improved adhesion, especially to glass, the caulks
and sealants may comprise one or more organosilane adhesion
promoter in amounts ranging from 0.001 to 5 wt. %, based on the
total weight of the composition, preferably, 0.01 wt. % or more,
or, preferably, up to 1.0 wt. %, or, more preferably, up to 0.5 wt.
%. Suitable organosilanes may include, for example, any
hydrolyzable or alkoxy functional organosilanes, such as, for
example, trialkoxysilanes; aminoalkylsilanes or aminoalkoxysilanes,
such as y-aminopropyl triethoxysilane and
N-(dimethoxymethylsilylisobutyl) ethylenediamine; epoxy functional
alkoxysilanes, such as glycidyl propoxymethyl dimethoxysilane,
y-glycidoxypropyl-methyl-diethoxysilane, y-glycidoxypropyl
trimethoxysilane, and 13-(3,4-epoxycycyclohexyl)ethyl
trimethoxysilane; (meth)acryloyl alkoxysilanes, such as
y-methacryloxypropyl trimethoxysilane; vi nyltriethoxysilane, and
y-mercaptoalkoxysilanes.
[0059] To enable improved filler dispersion and uniformity in the
composition, the aqueous caulks and sealants may comprise one or
more dispersant which can be an organic dispersant, e.g. a
carboxylic acid (co)polymer, such as poly(methacrylic acid), or
inorganic dispersant, such as alkali(ne) metal salts of
tripolyphosphates, metaphosphates and their salts, and
hexametaphosphates and their salts. Suitable amounts of dispersants
may range from 0.01 to 5 wt. %, based on the total weight of the
aqueous composition, preferably, 0.02 to 2 wt. %, or, more
preferably, 0.1 to 1.0 wt. %. Solvents may be added to improve
tooling in use, increase open time (storage stability) and to
better disperse additives, such as the silanes. Suitable solvents
may include, for example, mineral spirits, turpentine, mineral oil,
and (poly)alkylene glycols. Solvents are not plasticizers and are
volatile in use conditions.
[0060] The compositions of the present invention may also include
other additives conventionally employed in caulks and sealants,
such as, for example, free-thaw stabilizers, drying oils, biocides,
antifoamants, colorants, waxes and anti-oxidants.
[0061] Surfactants and emulsifiers commonly used in emulsion
polymerization may be present as formulation additives. These
include anionic, nonionic, and cationic surfactants, such as, for
example, non-ionic surfactants, like alkylphenol ethoxylates (APEO)
or APEO-free surfactants. In one embodiment, surfactants can be
added to the latices during synthesis as post additives.
[0062] The aqueous caulk and sealant compositions may be applied as
a caulk or a spray sealant. Thus, they may be used as kits
comprising a caulk or sealant, such as in a squeeze tube, a
cartridge or sausage pack adapted for use with a caulk gun, spray
nozzle, a pressurized, gunless applicator, or in a pail or can,
adapted for use with a bulk applicator such as a spray unit.
[0063] The compositions of the present invention are suitable for
uses including applying the caulk and sealant to a substrate and
allowing it to dry. Caulks and sealants can be applied to various
substrates including wood, glass, metal, masonry, vinyl, brick,
concrete block, fiber cement, gypsum, stone, tile and asphalt. Uses
may include caulking and sealing windows, doors, fixtures,
paneling, molding, finished walls and ceilings, and any gap, seam
or joint therein or between substrate pieces, such as in tilt-up
construction and chinking applications
EXAMPLES
[0064] The following examples illustrate, but do not limit, the
present invention. Unless otherwise indicated, all procedures were
performed at room temperature. In the examples, the following
chemical abbreviations are used:
[0065] AA: Acrylic Acid; BA: Butyl Acrylate; EA: Ethyl Acrylate;
EHA: 2-Ethylhexyl Acrylate; MAA: Methacrylic Acid; MMA: Methyl
Methacrylate.
Examples 1, 3, 5, 7, 9, 11, 13, 15, 17 and 18
Synthesis of Emulsion Copolymer Composites By Powerfeed Emulsion
Polymerization
[0066] Emulsion polymerization was carried out in a four neck 5
liter round bottom reaction flask equipped with a condenser, a
mechanical stirrer, a thermocouple, a monomer feed line, an
initiator feed line and a nitrogen inlet. 450 g of deionized water
was added to the flask and its contents were heated to 90.degree.
C. under nitrogen sweep with stirring. To the reactor mixture at
90.degree. C., a solution containing 2.9 g of sodium sulfate and
1.9 g of sodium carbonate dissolved in 30.8 g of water was added
followed by 1.9 g of DISPONIL FES-993 (Cognis Corp, Ambler, Pa.),
an anionic surfactant of fatty alcohol polyglycol ether sulfate in
14.9 g of water and 117 g of acrylic seed emulsion polymer 45 wt. %
solids (particle size 40 nm) and a solution consisting of 7.0 g of
ammonium persulfate in 33.8 g of water to form a reaction
medium.
[0067] In a separate vessel from the reaction flask, as shown in
Table 1, below, a monomer emulsion (ME) was prepared by mixing
using a magnetic stirrer the indicated ingredients including
surfactant 1 (surf 1), surfactant 2 (surf 2) and monomers. In
another separate vessel, a solution consisting of 2.3 g of ammonium
persulfate (APS) in 110 g of water and a buffer solution consisting
of 2.0 g of sodium sulfate (NaS) and 1.0 g of sodium carbonate
(Na.sub.2CO.sub.3) in 110 g of water were prepared.
[0068] With the reaction medium in the reaction flask temperature
at 82 to 86.degree. C., the ME was fed into the reaction over a
total monomer feed time of 120 minutes together with a cofeed of
the APS and buffer solution. The temperature of the reaction
mixture was held at 85.degree. C. during the polymerization. After
feeding ME until the indicated portion of the total ME feed (Soft
feed in Table 1, below) has been fed into the reaction flask, the
hard comonomer feed into the monomer emulsion vessel. The ME feed
ended at the same time. At the end of the feed, the temperature of
the reaction mixture was held at 85.degree. C. for 10 minutes
follow by cooling.
[0069] The product emulsion copolymers had solids contents ranging
from 40 to wt. % to 65 wt. %.
[0070] The final compositions of each emulsion copolymer are
presented in Table 3, below.
TABLE-US-00001 TABLE 1 Aqueous Emulsion Copolymer Compositions Soft
Hard Co- Water Surf 1.sup.1 Surf 2.sup.2 Monomer Emulsion (ME) (g)
feed monomer Example (g) (g) (g) BA EHA EA MMA AA (wt. %) MMA 1 284
20.7 9.5 1425 0 0 0 75 50 375 3 284 20.7 9.5 0 1425 0 0 75 50 375 5
284 20.7 9.5 0 1237.5 0 0 75 50 562.5 7 284 20.7 9.5 0 1012.5 412.5
0 75 50 375 9 284 20.7 9.5 0 712.5 712.5 0 75 50 375 11 284 20.7
9.5 0 806 806 0 75 50 187.5 13 284 20.7 9.5 712.5 712.5 0 0 75 50
375 15 284 20.7 9.5 0 1140 0 285 75 50 375 17 284 20.7 9.5 0 1012.5
412.5 0 75 0 375 18 284 20.7 9.5 0 1012.5 412.5 0 75 75 375
.sup.1Surfactant 1: DISPONIL FES-993 (Cognis), anionic fatty
alcohol polyglycol ether sulfate; .sup.2Surfactant 2: TERGITOL
15-S-9 (The Dow Chemical Company), nonionic secondary alkyl
ethoxylate; 3. Percent of the total soft monomer composition fed
into the polymerization vessel before the start of the feed of hard
monomer being fed into the ME. The feed rate of the soft monomer
composition was held constant, with the feed rate of the hard
comonomer composition adjusted to end at same time as the soft
monomer composition feed. The total feed time of the monomer
emulsion with the powerfeed stage was 120-140 minutes.
Comparative Examples 2, 4, 6, 8, 10, 12, 14 and 16
Synthesis of Comparative Emulsion Copolymers
[0071] Emulsion polymerization was carried out in a four neck 5
liter round bottom reaction flask was equipped with a condenser, a
mechanical stirrer, a thermocouple, a monomer feed line, an
initiator feed line and a nitrogen inlet. 450 g of deionized water
was added to the flask and the content was heated to 90.degree. C.
under nitrogen gas sweep with stirring. To the reactor mixture at
90.degree. C., a solution containing 2.9 g of sodium sulfate and
1.9 g of sodium carbonate dissolved in 30.8 g of water was added
followed by 1.9 g of DISPONIL FES-993 (Cognis), an anionic
surfactant of fatty alcohol polyglycol ether sulfate in 14.9 g of
water and 117 g of seed emulsion polymer (acrylic emulsion polymer
with 45 wt. % solids and particle size 40 nm and a solution
consisting of 7.0 g of ammonium persulfate in 33.8 g of water to
form a reaction mixture.
[0072] In a separate vessel from the reaction flask, a monomer
emulsion (ME) was prepared by mixing the ingredients using a
magnetic stirrer as indicated in Table 2, below, including
surfactant 1 (surf1), surfactant 2 (surf2) and monomers. In
separate vessel, a solution consisting of 2.3 g of ammonium
persulfate (APS) in 110 g of water and a buffer solution consisting
of 2.0 g of sodium sulfate (NaS) and 1.0 g of sodium carbonate
(Na.sub.2CO.sub.3) in 110 g of water was prepared.
[0073] With the reaction mixture in the reaction flask temperature
at 82 to 86.degree. C., ME was fed into the reaction over a total
feed time of 120 minutes together with the cofeed of the APS
solution and buffer solution. The temperature of the reaction
mixture was held at 85.degree. C. during the polymerization. At the
end of the feed, the temperature of the reaction mixture was held
at 85.degree. C. for 10 minutes follow by cooling.
[0074] The product emulsion copolymers had solids contents ranging
from 40 wt. % to 65 wt. %.
[0075] The final compositions of each emulsion copolymer are
presented in Table 3, below.
TABLE-US-00002 TABLE 2 Comparative Aqueous Gradual Addition
Copolymer Compositions Comparative Monomer Emulsion (ME) Example
Water Surf 1.sup.1 Surf 2.sup.2 BA EHA EA MMA AA 2 284 20.7 9.5
1425 0 0 375 75 4 284 20.7 9.5 0 1425 0 375 75 6 284 20.7 9.5 0
1237.6 0 562.5 75 8 284 20.7 9.5 0 1012.6 412.5 375 75 10 284 20.7
9.5 0 712.5 712.5 375 75 12 284 20.7 9.5 0 806.3 806.3 187.5 75 14
284 20.7 9.5 712.5 712.5 0 375 75 16 284 20.7 9.5 0 1140 0 660 75
.sup.1Surfactant 1: DISPONIL FES-993 (Cognis), anionic fatty
alcohol polyglycol ether sulfate .sup.2Surfactant 2: TERGITOL
15-S-9 (The Dow Chemical Company), nonionic secondary alkyl
ethoxylate.
[0076] The emulsion copolymers of Examples 17 and 18 were made in
the same manner as the emulsion copolymer of Example 7, except that
for Example 17 the soft monomer ME feed is begun simultaneously
with the feed of the hard monomer into the soft monomer vessel
(time period equals 0 or 0%). Therefore, no distinct soft polymer
phase is generated. The difference between Example 17 and Example 8
is that the polymer of Example 17 has a gradient composition and
Example 8 has a random and narrow distributed composition. Example
18 has a time period of 75% of the total monomer feed time before
the hard monomer feed into the soft monomer vessel is begun, which
resulted in a higher proportion of the soft composition. Example 7,
17, 18 and 8 all have exactly the same overall monomer composition.
The changes in the synthetic method resulted in distinct polymeric
products.
[0077] The emulsion copolymers of Examples 1, 3, 5, 7, 9, 11, 13,
15, 17 and 18 and some or all of the emulsion copolymers of
comparative Examples, 2, 4, 6, 8, 10, 12, 14, 16 and 19-22 were
tested using the following test methods:
[0078] Low Temperature Flex (LTF): Emulsion copolymers as
synthesized were drawn down on 10 cm.times.23 cm aluminum panels
with a 1 mm draw down bar. The drawn emulsion copolymer layers were
allowed to dry for 4 days at room temperature and were then put in
a vacuum oven for 12 hrs at 60.degree. C. Aluminum panels were cut
into 7.6 cm length and 2.56 cm width strips. The strips were then
placed into a cold box at 244.degree. K. for 2 hours followed by
bending over a 1.27 cm dowel. The sample failed flexibility at the
temperature if the sample cracked on bending.
[0079] If this test was performed at a different temperature, then
each time the temperature was varied the emulsion copolymers were
drawn down and allowed to sit at that temperature for 2 hours
before testing.
[0080] Tack Evaluation: Emulsion copolymers as synthesized were
drawn down on 10 cm.times.23 cm aluminum panels with a 1 mm draw
down bar. The samples were allowed to dry for 4 days at room
temperature. The samples were then put in a vacuum oven for 12 hrs
at 60.degree. C. The samples were then evaluated with the touch of
a finger and were rated using the following scale: 5 =Very Very
Tacky; 4 =Very Tacky; 3=Moderately Tacky; 2=Slightly Tacky; 1=No
Tack.
[0081] Tensile/Elongation: Emulsion copolymer samples (8 g polymer
solids after drying) as synthesized were poured into 10 cm diameter
petri dishes and let dry at room temperature for 14 days. At 7 days
the samples were flipped over to promote drying. Samples were then
cut into 1.27 cm wide by 7.6 cm long strips and a thickness range
between 0.9 mm to 2.0 mm. The dried emulsion copolymer strips were
tested using a Tinius Olsen, Inc. (Horsham, Pa.) device with a
gauge length of 2.54 cm and pulled apart at a rate of 2.54 cm/min.
until they broke. The length of the strip at break was recorded as
% Elongation with respect to the original length. The tensile
strength at break was recorded as T.sub.Break and the maximum
tensile strength reached before the break was recorded as T.sub.max
The Tmax, Tbreak and % Elongation of each strip were then recorded.
The result given below is the average of 3 strips tested.
[0082] Dynamic Mechanical Analysis: A 16 g sample of the indicated
wet emulsion copolymers were poured into TEFLON.TM. polymer Petri
dishes and allowed to air dry for 48 hr. Each of the dried samples
was inverted and allowed to further dry for 24 hours. Each of the
Petri dishes was then dried for eight hours at 40.degree. C. and
placed in a vacuum oven until use. The resulting dried emulsion
copolymer samples were then tested under shear on a Rheometrics
Mechanical Spectrometer (RMS-800) (TA Instruments, New Castle,
Del.) using 8 mm diameter disposable parallel plate fixtures.
[0083] Prior to measurement, the thickness of each dry sample was
measured to the nearest 0.001 mm and the data were input into the
instrument to calculate the shear moduli. A temperature sweep was
run from 150.degree. C. to -50.degree. C. at a cooling rate of
2.degree. C/min using the Dynamic Temperature Ramp Mode of the
spectrometer. The applied frequency was 6.28 rad/s (1 Hz) and both
AutoTension and AutoStrain options were employed during the test.
The initial strain was 0.25%. For each dry sample, the dynamic
storage and loss moduli (G' and G'', respectively) as well as tan
.delta. of the dry samples were recorded as a function of
temperature.
TABLE-US-00003 TABLE 3 Emulsion Copolymer Compositions Polymer-
ization Example Emulsion Copolymer Method.sup.1 1 76 BA/20 MMA/4 AA
PF *2 '' R 3 76 EHA/20 MMA/4 AA PF *4 '' R 5 66 EHA/30 MMA/4 AA PF
*6 '' R 7 54EHA/22EA20MMA/4AA PF *8 '' R 9 38EHA/38EA/20MMA/4AA PF
*10 '' R 11 43EHA/43EA/10MMA/4 AA PF *12 '' R 13 38EHA/38BA/20MMA/4
AA PF *14 '' R 15 60.8 EHA/35.2MMA/4 AA PF *16 '' R *17 ]
54EHA/22EA/20MMA/4AA (0% Time period) PF 18 ] 54EHA/22EA/20MMA/4 AA
(75% Time Period) PF *19 BA/MMA/MAA Random Copolymer with Tan R
Delta peak at 2.degree. C. *20 BA/MMA/MAA Random Copolymer with Tan
R Delta peak at -8.degree. C. *21 EHA/BA/MMA/MAA Random Copolymer
with R Tan Delta peak at -27.degree. C. *22 BA/MMA/MAA Random
Copolymer with Tan R Delta peak at 8.degree. C. .sup.1PF: Powerfeed
method; R: Random Copolymer. *comparative example
[0084] The results of the testing of emulsion copolymer films is
presented in Tables 4 and 4B, below. The results of the testing of
clear caulk films made from the emulsion copolymers is presented in
Table 5, below. The results of the testing of filled caulks made
from the emulsion copolymers is presented in Table 6, below.
TABLE-US-00004 TABLE 4 Clear Film Properties Modulus (G') Tensile
Properties (dyne/cm.sup.2 E-6) Tan .delta. LTF T.sub.max
T.sub.Break Elong Example 0 10 20 40 (.degree. C.) (.degree. C.)
Tack .sup.1 MPa MPa (%) 1 470 280 100 3 -30, 35 -45 S-2 0.13 0.11
710 *2 150 4.5 2.8 1.4 -6 -25 V-4 0.20 0.11 1987 3 200 55 10 1.4
-58, 23 -49 S-2 0.24 0.21 645 *4 3.2 1.2 1.2 0.66 -19 -40 V-4 0.20
0.14 1202 5 1200 790 530 120 -62, 54 -35 N-1 0.54 0.41 487 *6 24
6.2 3 1.4 -3 >-25 V-4 0.32 0.12 1818 7 500 260 55 2.2 -35, 30
-35 S-2 0.18 0.13 757 *8 1.6 5.1 2.8 1.5 -6 -25 V-4 0.26 0.15 1628
9 620 280 37 2.1 -23, 26 -25 S-2 0.12 0.08 1541 *10 48 7.6 3 1.1 1
>-25 T-3 0.23 0.12 2250 11 10 3.5 1.8 0.7 -0.6 NA NA 0.13 0.10
2710 *12 8 3 2 0.9 -10.5 NA NA 0.15 0.09 1694 13 310 66 8 1.4 -40,
20 -45 T-3 0.16 0.13 1184 *14 7 3 1.8 1 -11 -25 V-4 0.18 0.12 1544
15 400 220 110 15 -20, 43 -30 N-1 0.42 0.29 965 *16 300 20 9 2.8 7
>-25 S-2 0.49 0.21 2380 *17 34 7.3 3.1 1.3 2.3 0.22 0.15 2130 18
180 140 93 48 -28, 38 0.23 0.16 575 *19 90 11 4.4 2.1 2 2 S-2 0.14
0.14 2160 *20 9 3.2 1.8 0.7 -8 -8 V-4 0.12 0.10 2870 *21 1.8 1 0.8
0.5 -27 -27 VV-5 0.09 0.07 1710 .sup.1 N = no tack (1); S = Slight
(2); T or Mod = Tacky (3); Mod to Sev or V = Very tacky (4); Severe
= VV = Very Very Tacky (5); *comparative example
TABLE-US-00005 TABLE 4B Clear Film Properties. Modulus (G')
(dyne/cm.sup.2 E-6) Example -30 -20 -10 0 10 20 40 1 1973 1033 700
470 280 100 3 *2 4414 2623 180 150 4.5 2.8 1.4 3 965 634 400 200 55
10 1.4 *4 528 46 8.4 3.2 1.2 1.2 0.66 5 1494 1317 1116 1200 790 530
120 *6 3930 1940 275 24 6.2 3 1.4 7 1685 1112 778 500 260 55 2.2 *8
4099 1646 122 1.6 5.1 2.8 1.5 9 2380 1457 982 620 280 37 2.1 *10
3077 2530 919 48 7.6 3 1.1 11 1996 527 96 10 3.5 1.8 0.7 *12 3678
797 38 8 3 2 0.9 13 1318 944 632 310 66 8 1.4 *14 2681 458 28 7 3
1.8 1 15 2538 1222 658 400 220 110 15 *16 4867 3937 2003 300 20 9
2.8 *17 1983 1120 268 34 7.3 3.1 1.3 18 6267 253 169 180 140 93 48
*19 4688 4302 2657 90 11 4.4 2.1 *20 4162 2125 81 9 3.2 1.8 0.7 *21
109 9.4 3.2 1.8 1 0.8 0.5 N = no tack (1); S = Slight (2); T or Mod
= Tacky (3); Mod to Sev or V = Very tacky (4); Severe = VV = Very
Very Tacky (5); *Comparative example.
[0085] As shown in Table 4, above, the inventive emulsion
copolymers all exhibited much improved tack and low temperature
flexibility as well as modulus at all temperatures tested when
compared to the same emulsion copolymer made by random
copolymerization. For the inventive emulsion copolymers, the
modulus value below the Tg of the random copolymer is lower than
that of the inventive polymer and the modulus value above the Tg of
the random copolymer is higher than that of the inventive polymer.
This indicates superior polymer properties at temperatures on both
side of the Tg with respect to the random copolymer. As shown in
Table 4B, above, comparing the emulsion copolymer and their
corresponding random copolymer comparatives having identical
overall monomer compositions, respectively, in Examples 1 and 2; 3
and 4; 5 and 6; 7 and 8; 9 and 10; 11 and 12; 13 and 14; 15 and 16,
the dynamic mechanical analysis (DMA) demonstrates that the modulus
transition behavior of a soft copolymer can be made to mimic that
of a high Tg polymer without losing the soft polymer properties in
the compositions. The soft properties of the polymeric composites
(flexibility and softness) are exemplified by the lowered modulus
at temperatures below the glass transition temperature. As shown in
Table 4, above, in Examples and corresponding comparatives,
respectively, Examples 1 and 2; 3 and 4; 5 and 6; 7 and 8; 9 and
10; 11 and 12; 13 and 14; 15 and 16, the two Tan Delta transitions
in the inventive emulsion copolymers demonstrates the presence of a
much harder polymer phase in the emulsion copolymer binder of the
present invention when compared to random copolymers made from the
same monomer mixture which lack a second transition or one at such
a high temperature.
[0086] The clear caulks in Table 5, below were formulated from the
emulsion copolymers of the indicated Example by mixing 100 g of the
emulsion polymer with 3.7 g of aqueous ammonia (28 wt. % solution)
by a SpeedMixer.TM. DAC 400 FVZ (FlackTek, Inc., Landrum. S.C.) at
2000 rpm for 1 minute followed by the addition of 0.8 g of
Acrysol.TM. TT-615 thickener (The Dow Chemical Company) with an
additional 1 minute of mixing at 2000 rpm. The viscosities of the
caulks ranged from 100,000 to 350,000 cPs.
TABLE-US-00006 TABLE 5 Clear Caulk Evaluation Example LTF (.degree.
C.) Tack.sup.1 1 -30 Slight-2 *2 0 4 3 -20 Mod-3 *4 -20 Sever-5 5
-20 None-1 *6 >0 Mod-3 7 0 Slight-2 *8 0 Mod-Sev - 4 *17 >0
Mod-3 18 -10 Slight-2 *19 >0 Slight-2 *20 -20 Mod-3 *21 <-40
Sever-5 *22 >0 None-1 .sup.1N = no tack (1); S = Slight (2); T
or Mod = Tacky (3); Mod to Sev or V = Very tacky (4); Severe = VV =
Very Very Tacky (5); *comparative example
[0087] As shown in Table 5, above, the clear caulk formulations of
the inventive emulsion copolymers all have improved tack and low
temperature flexibility when compared to the same caulk formulation
have the same emulsion copolymer made by random
copolymerization.
[0088] The filled caulks in Table 6, below were formulated from the
emulsion copolymers of the indicated Example by mixing 83 g of the
indicated emulsion copolymer with 13.5 g of Drikalite (CaCO.sub.3),
0.5 g of Ti Pure R-900 (DuPont, Wilmington, Del.) by SpeedMixer.TM.
DAC 400 FVZ (FlackTek) at 200 rpm for 1 minute, following by the
addition of 0.7-1.4 g of aqueous ammonia (28%) to a pH of 7.5 to
7.7 and mixing for 1 minute. The mixture was thickener by slow
addition of 0.2 to 1.0 g of Acrysol TT-615 (a
hydrophobically-modified alkali swellable emulsion polymer from The
Dow Chemical Company) with continous mixing with a bench top
mechanical mixer. The viscosities of the caulks ranged from 100,000
to 500,000 cPs.
TABLE-US-00007 TABLE 6 Evaluation Of Filled Caulks Example LTF
(.degree. C.) Tack.sup.1 1 -20 None-very slight 1-2 *2 -10 Mod-3 5
+20 None-1 *6 +10 Slight-2 7 0 Slight-2 *8 +10 Mod-3 *17 +10 Mod-3
18 -10 None-very slight 1-2 *19 +10 *20 -10 *21 -40 Severe-5 *22
>+20 None-1 .sup.1N = no tack (1); S = Slight (2); T or Mod =
Tacky (3); Mod to Sev or V = Very tacky (4); Severe = VV = Very
Very Tacky (5); *comparative example.
[0089] As shown in Table 6, above, the filled caulk formulations of
the inventive emulsion copolymers all have improved tack and all
but the caulk of Example 5 have improved low temperature
flexibility when compared to the same caulk formulations that have
the same emulsion copolymer made by random copolymerization. The
Example 5 emulsion copolymer comprises more than the most preferred
proportion of copolymerized hard phase monomers and the MMA hard
phase monomer gives a polymer having a Tg at the endpoint of the
preferred hard comonomer Tg range.
TABLE-US-00008 TABLE 7 Exemplary Caulk Viscosities Emulsion
Copolymer Viscosity Solids Example (g) NH.sub.3 (g) Thickener.sup.1
(cP) (Wt. %) 3 835.6 15.7 7.6 240-251K 61.3 5 832.4 15.0 11.7
220-238K 61.0 *4 826.0 16.9 16.1 168-172K 60.6 *6 839.1 14.6 5.3
119-125K 61.5 *21 843.3 5.4 11.9 124-129K 61.7 *comparative
example. .sup.1ACRYSOL .TM. TT-615 (The Dow Chemical Company) a
Hydrophobically modified Alkali Soluble Emulsion supplied as a
unneutralized emulsion at 30% total solids.
[0090] The caulks and sealants, both inventive and comparative,
have high Brookfield viscosities at room temperature and at a pH of
8-9. By using a buffer in polymerization and not neutralizing the
emulsion copolymer, one can keep the viscosity of the emulsion
copolymer low prior to formulating it into a caulk or sealant
composition.
* * * * *
References